Cholesterol granuloma in thyroglossal cysts: a clinicopathological study.

Thyroglossal duct cyst (TDC) is a congenital anomaly caused by retention of epithelial remnants from the descent of the thyroid gland during embryological development. Cholesterol granuloma represents a granulomatous reaction to precipitates of cholesterol crystals in tissue, usually related to middle-ear disease. The association of TDC with cholesterol granuloma has hardly been reported. This study describes five patients with TDC and cholesterol granuloma over a 16-year-period. The treatment consisted of excision of the TDC and the mid-portion of the hyoid bone and excision of a core of tissue between the hyoid bone and the foramen cecum (Sistrunk procedure). We speculate that the pathogenesis of cholesterol granuloma in TDC resembles that in the paranasal sinuses, as both sites provide a closed, poorly ventilated hollow structure with slow drainage. Our five patients accounted for 13% of all patients with TDC treated in our center during the same period, indicating that cholesterol granuloma in TDC may not be as rare as previously thought.